Seven Reverse Y #1 Reservoir Report

Last Updated: December 5, 2025

Seven Reverse Y #1 is a private irrigation dam located in Weld County, Colorado, along Willow Creek.


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Summary

Built in 1965, this Earth dam stands at a height of 29 feet and spans 630 feet in length, with a storage capacity of 273 acre-feet. The dam serves multiple purposes, including irrigation, fire protection, stock maintenance, and flood risk reduction, making it a crucial water resource infrastructure in the region.

Managed by the Department of Water Resources (DWR) in Colorado, Seven Reverse Y #1 has a low hazard potential and is assessed to be in fair condition as of the last inspection in May 2009. With a spillway width of 352 feet and a maximum discharge capacity of 10,690 cubic feet per second, the dam plays a vital role in managing water flow and ensuring water security in the area. Climate enthusiasts and water resource experts will find this dam an essential piece of infrastructure contributing to sustainable water management practices in the region.

As a part of the Omaha District, Seven Reverse Y #1 is subject to state regulation, inspection, and enforcement to ensure its safety and functionality. With its moderate risk assessment rating, the dam is monitored regularly to mitigate any potential hazards and maintain its operational efficiency. For those passionate about water resource management and climate resilience, Seven Reverse Y #1 represents a critical piece of infrastructure supporting agricultural activities and water sustainability in Weld County, Colorado.

Year Completed

1965

Dam Length

630

Dam Height

20

River Or Stream

WILLOW CREEK

Primary Dam Type

Earth

Surface Area

5

Hydraulic Height

20

Drainage Area

59

Nid Storage

273

Structural Height

29

Hazard Potential

Low

Nid Height

29
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.